I have never actually seen one of these machines myself, but the information on what they can do is pretty much public knowledge.

It detects anomalies. Things in pockets or pretty much anything on top of the individuals skin including clothing. And of course any anomalies must be investigated further. I know for a fact that they can detect small amounts of marijuana in people’s pockets, we get reports on it every day. It does not detect it as marijuana but as an anomolie.